Vacuum packaging



5 Sheets-Sheet 1 Filed May .10, 1955 FIG. 4

Inventor Hubert Percival Schofield K Attorney May 9, 1961 I H. P.SCHOFIELD VACUUM PACKAGING 3 Sheets-Sheet 2 Filed May 10, 1955 InventorHubert Percival Schotiuld Ute Patented May 9, 1961 VACUUM PACKAGINGHubert Percival Schofield, 197 'Abbotts Drive, Wembly, England Filed May10, 1955, Ser. No. 507,359

2 Claims. (Cl. 53-14) The present invention relates to the production ofairtight sealed packages of plastic, flexible or other yieldablematerial.

The primary object of the present invention is to provide simple meansfor evacuating air from, and sealing, packages of the kind referred to,in order to preserve the commodities contained therein until the timearrives for their consumption or use. An example of this arises in thepackaging of alimentary material such as sandwiches or meat where theexclusion of air has the eifect of preventing the development ofbacteria and the maintenance of the contents in a fresh condition untilsuch time as the seal is broken.

In the production of a package according to the present invention thereis used an insert of cardboard, metal or other relatively stiff materialwhich has a hole therein and a slot extending from said hole to one ofits edges to enable suction applied to the hole in the insert, when thelatter is located coincidental with a corresponding hole in the wall ofthe package, to be exerted substantially uniformly within the packageover the entire perimeter of the insert. p 7

The invention also includes the step of transversely sealing a packageacross its entire width both above and below the insert so thatsubsequent to the application of vacuum and sealing the insert lieswholly within the package yet outside the commodity containing partthereof.

In the preferred form of construction of insert, this has a dualfunction in that after being located within the mouth of a package withthe hole of the insert coinciding with coaxial holes in opposed sidewalls of the package, and after the said mouth has been sealed with theinsert enclosed within the package it is adapted to operate not only inthe application of vacuum extensively within the package but also insupporting the package during the application of said vacuum theretothrough the coincident holes and during the final sealing of the packagewith the insert isolated from the commodity containing part thereof.

The method of production as a whole is characterised in that a flatelement of cardboard, metal or other relatively stiff material, whichhas a hole therein and a slot extending from said hole to one of itsedges to enable suction applied to said hole to be exerted substantiallyuniformly over the perimeter of the element, is inserted into the mouthof a commodity containing package with its hole coincident with those inthe package walls, the edges of the mouth are sealed to enclose theinserted element, vacuum is applied to the coincident holes to partiallyor wholly evacuate air from the package, and the package is finallysealed to isolate the inserted element from the commodity containingpart of the package.

The initial sealing above the insert may 'be of a temporary natureachieved for example by the use of clamping jaws, i.e. it may bemaintained solely until the required vacuumizing and final sealing toisolate the insert from the commodity containing part of the packagehave been achieved. This is particularly the case where after thecommodity retaining part of thepackage has been scaled from the insertretaining part it is desired to remove the insert for any reason, suchas for example to enable it to be used afresh in the application ofvacuum to other packages. Otherwise the seal above the insert may be aspermanent as that isolating the insert from the contents and may beapplied in the same manner.

It is also to be understood that where desired an inert or neutral gas,powders or liquids may be inserted into the packages at the terminationof the vacuumizing step and prior to final sealing.

The invention is more particularly described with reference to theaccompanying drawings in which:

Figure l is a view of a sealed package with the insert isolated from theenclosed commodities.

Figure 2 is a section on the lines 22 of Figure 1.

Figure 3 shows the insert in plan view.

Figure 4 is an end view of the insert of Figure 3.

Figure 5 is a diagrammatic representation of the cycle of operations inthe automatic handling of a package for vacuumizing and sealingpurposes.

Figure 6 is a diagrammatic representation of a general assembly utilisedin the production of a sealed and commodity retaining package.

Figure 7 is .a diagrammatic view on a larger scale of each of the heatsealing rollers of Figure 6.

Figure 8 is a diagrammatic representation of an automatic mechanism foruse in applying vacuum to the packages.

Figure 9 is a corresponding end view of the mechanism of Figure 8.

Figure 10 is a diagrammatic plan view showing the relative dispositionof the parts of a number of the elements of Figure 8.

Figures 11 and 12 are diagrammatic representations showing how sealingof a package may be achieved for a period during its continuous progressthrough a mechanical handling machine, as distinct from an instantaneoussealing operation. 7

In the construction according to Figures 1-4, a package or bag 10 offlexible, pliable, resilient or otherwise yieldable material such asplastic, cellulose, paper or even metal foil, has front and rear walls11, 12, sealed at their lower ends 13. Perforations 14 are formedadjacent the upper endor the open mouth of the package .in both oppositewalls to register one with the other and with a perforation 15 in aninsert 16 of flat cardboard,

thin metal or other relatively stiff and thick material,

tions simultaneously in the respective elements when the' insert 16 islocated in its operative position within the mouth of the package 10, oragain the holes 14, 15 may be formed during manufacture of the packagesand the inserts respectively, i.e. before they are brought together.

Bearing in mind that the insert 16 is not intended for insertion in thatpart of the package under vacuum and therefore its shape is not likelyto be distorted as happens to the package itself when it collapsesaround an object, any printed matter on the insert may be easily read,whereas printed matter on the package would become very distorted andunreadable Printing on the cardboard inserts instead of the packages isalso desirable,firstly, because it is much simpler and cheaper and,secondly, it is possible to have a standard package for a very largerange of products and only the printed matter on the cardboard insertsneed be diiferent.

The required indexing of an insert 16 within the mouth of a package sothat its hole will remain in registration with the holes 14 of thepackage throughout the handling operation is achieved by means of a pairof heat-sealed circles 17 adjacent the side edges of the package, theseheat-sealed circles reducing the width of the package available to thepassage of articles and thus retaining the insert in its desiredposition of operation provided of course that the width of the insert ismerely slightly less than that of the package, but is greater than thespacing apart of the circles.

Although a single hole 14, 15 is provided in the insert and in each wallof the package as the case may be, a pair of spaced holes may be formedin each element where this is thought to be desirable for enabling apackage and its contents to be supported from pins or pegs on an endlesstravelling conveyor and for simultaneously accurately positioning thepackage in travelling with said conveyor for the vacuumizing and sealingoperations.

A narrow slot 18 extends from the hole 15 to an edge 19, whichpreferably is the lower lateral edge, of the insert 16. For the purposeof meeting the particular requirements either of the commodities to behoused in the packages, or the nature of the packaging material and itsthickness, the speed of vacuumizing may be varied by using inserts 16 ofdifferent thicknesses and/or slots 18 of different widths. In thisrespect it will be appreciated that when suction is applied to a packagethrough the holes 14 of the package walls, the hole 15 of the insert andthe slot 18, a passage of substantially triangular cross section, thehypotenuse or longer width of which is constituted by the edges of theinsert, is available around the entire perimeter of the insert to ensurea relatively slow application of the vacuum to the package in contrastto instantaneous application which would have the eiiect of causing thepackage to adhere to its contents at different places tending to trapair in pockets within the package. Thus the width of the slot 18 in eachinsert should be so arranged, in proportion to the thickness of thecardboard, that under the heavy atmospherical pressures created on theoutside of the container by the vacuum inside, the material of thecontainer could not collapse inwards sufficiently to seal off thepackage before all the air was exhausted; the thickness of the cardboardwill also provide for the package collapsing tightly around it yet stillleaving a triangular shaped opening through which air can be evacuated.In general, it follows that the thinner the wall thickness of thepackage the thicker the cardboard should be, and also the narrower theslot, thus preserving an adequate space for air flow and minimising therisk of the package collapsing in a manner likely to leave isolated airpockets and to prevent total exhaustion.

The heat sealed circles 17 in the package walls may have V shapedindentations 29 therein to assist in severing the material forming thewalls when it is desired to obtain access to the sealed contents.Conveniently the angle of i the V shaped indentations is directedtowards the commodity retaining part of the package in order to directthe tears towards said portion.

As may be seen from Figure 5, the cycle of operations in the mechanicalhandling of commodity containing packages of the kind illustrated inFigure 1, may be continuous; thus the packages may be carried by acontinuously travelling endless conveyor 21 successively through anumber of stations at which different operations are performed. Thus thepackages 10, each with an insert 16, may manually be hung on theconveyor belt 21 at station 22, in a prefilled condition, or they may beprepared and filled at said station. They are then conveyed to station23 at which the mouth of the package above its insert is sealed eithertemporarily, such as for example by means of clamping jaws fitted withresilient pressure pads and travelling with the conveyor, or permanentlyuntil access to the commodity within the package is desired,

in which latter event heat-sealing may be achieved in any one of anumber of well known methods, such as for example with the aid of heatedsealing rollers.

The packages then travel towards the station 24, at which vacuum isapplied, and if desired the insertion of an inert or neutral gas,whereupon they move to the station 25 at which sealing of the packagesto isolate the inserts 16 from the commodity containing parts of thepackages is performed. The stations 24 and 25 may in fact overlapinasmuch as the final sealing operation of the station 25 may commenceand indeed be completed before the vacuum application is terminated.Removal of the filled and sealed packages from the conveyor 21 isachieved at station 26. In the conveyor belt 21 shown in the generalarrangement illustrated in Figure 6, and in the diagrammaticrepresentations oi Figures 8 and 9 spaced pegs 27 are provided so as toreceive the packages by engagement within the holes 14 thereof and theholes 15 of the inserts. Each peg 27 may support a rubber or the likewasher (not shown) at that end where it is carried by the conveyor toform a resilient seating for the vacuum or the like applicating devicewhen this is applied to the peg between the initial and final sealingstages of operation on the package it sup ports.

As may be seen from Figure 6 the endless conveyor 21 in its displacementin the direction of the arrows, is adapted to bring the packagessupported on its pegs 27 into engagement with a heat sealing roller 28of any desired form whereby, by virtue of the contact between ecahpackage 10 and the roller 28 as the former travels tangentially to thelatter, the package is transversely sealed at its mouth along one ormore lines or a band 28a determined by the heat-sealing periphery of theroller. A roller 29 located on the reverse side of the outward run ofthe conveyor 21 is adapted to hold up the conveyor 21 and each package10 to this upper heat-sealing roller 28 as pressure is applied by thelatter to the package.

Conveniently and as shown in Figures 6 and 7 the rollers 28, 29 areenclosed within endless belts 30 which over the major part of theirlength are maintained out of contact with the rollers by resilientlyloaded jockey pulleys 3 1 so that the belts themselves over a portion oftheir respective traverses are in contact with the packages 10 duringthe displacement of the latter so as to enable at least a low pressureto be applied for a period of time to the packages immediately afterheat-sealing has been effected. Again, rigid pressure plates 32 loadedby springs 32a are adapted to guide the belts over those portions oftheir paths where they are required to maintain pressure contact withthe packages. The small pressure belts 30 around the rollers 29 are madeof a material which will not adhere to hot plastic.

After leaving the upper sealing roller 28 and its associated belt 39,each package moves towards the station at which vacuumizing is effected.Although not shown in Figure 6 the application of suction commences asthe leading edge of each package 10 is about to enter the bight betweena lower sealing roller 33 and a corresponding roller 34 in engagementwith and on the opposite side of the outward run of the conveyor 21. Bylower sealing roller is meant the roller for heat sealing each packageimmediately below its insert, i.e. along lines or a band 33a (Figure 1),to isolate this from the commodity retaining part. The suction effect isdiscontinued when the rear edge of each package has just passed throughthe bight between the rollers 33, 34. Conveniently, and as shown inFigure 1, the sealed band 33a extends between the opposite heat sealedcircles 17 and the V shaped indentations 20 therein, but if desired itmay span the package at a position slightly below said circles.

The sealed packages are removed from the conveyor 21 in the region of aroller 35, a number of which may '5 be provided throughout the length ofthe conveyor to maintain this horizontal. The conveyor at the end of itsrun passes around a guide roller 36' to commence the return run in whichthe cycles of operations is repeated, and in this respect the rollers34, 29 again function respectively to hold up the conveyor and itspackages during the application of upper sealing by a sealing roller 37and lower sealing by another roller 38.

The upper heat-sealing rollers 28, -37 and the lower heat-sealingrollers 33, 38 may if desired be replaced by flexibly or resilientlycushioned sealing jaws diagrammatically represented at 39 in Figures 11and 12. These jaws whenin gripping engagement with opposed walls of apackage to seal them are adapted to hunt on an endless conveyor so thatthey travel with the packages during the sealing operation over apredetermined path of package displacement and then are returned out ofcontact with the packages to their starting positions for repeating thesealing operation on following packages. Thus the'jaws may be displacedalong an endless path represented by the perimeter of a multi-sidedfigure, such as for example the rectangle 40 of Figure 11 or again thetriangle 41 of Figure 12 one side only of which constitutes part of thedisplacement path of the packages on the conveyor 21 during sealing andthe application of vacuum.

A suitable device of a mechanical handling machine for controllingthe'application of vacuum to the packages as they travel continuouslywith the conveyor 21 over the distance between the sealing rollers 28,33 or again over the distance between the sealing rollers 37, 38 isdiagrammatically illustrated in Figures 8-10. In these figures a longarm having a rigid head part 42 and a resilient shank 43 is pivoted to aframe of the machine at 44 and is urged by a spring 45 towards the lefthand side of Figure 8, to take up the position shown in Figure 8, i.e.against a fixed stop 48. The resilient shank 43 is normally urgedtowards the vertical plane of the conveyor 21, i.e. towards the left inFigure 9 whilst the rigid head part 42 which is substantially of T shapecarries the vacuum appliance 46 and its lead 47.

An arm 49 is pivotally mounted at 50 to a fixed part of the machine andis urged towards the left (Figure 8) by a spring 51, anchored at 52,against a stop 53 determining its limiting end position. This arm 49 islocated within the path of displacement of the pegs 27 with the conveyor21 so as to be angularly displaced to the right of Figure 8 about itspivot 50 as it is engaged by each peg 27. Such angular displacementcontinues until the free end of the arm 49 descends below the line oftravel of the pegs, whereupon on being released from engagement by a peg27 said arm 49 springs back toward its stop 53 to impinge in saiddisplacement against a horizontal limb 54 of a pivotal lever 55 which isnormally resiliently held by a spring 56 against a stop 57 (Figure 8),and in such position lies in the path of the head 42 to the left (Figure9). The tension of the spring 56 is greater than that of the spring 52so that normally the arm 49 cannot reach its stop 53 whilst the limb 54of the pivotal arm 55 lies in its path except when by virtue of itsspeed of return from engagement with a peg 27 the arm 49 impinges withforce against the lever 55 and momentarily knocks the latter to the leftagainst the load of its spring 56. When this occurs, the head 42carrying the vacuum appliance which is normally held away from theconveyor, is freed so as to enable it to move toward the conveyor forengagement with a peg 27 thereof and thence be displaced with saidconveyor by virtue of said peg.

An arm 58, pivoted to a link 59 by which it is supported from above asdiagrammatically represented by a fixed member 60, is normallyresiliently urged with its free end 61 located against a ramp 62, sothat it lies in the path of the head 42 when the latter, freed fromoverlapping engagement with the lever 55, is in engagepurposes can beregarded as'a straight line so that the ment with a peg 27 and moveswith said peg and its conveyor 21.

veyor 21 and its spaced pegs 27 travelling to the right in the directionof the arrow. When a peg 27 abuts against the upper end of the arm 59 itcarries it with it until the arc of displacement of said upper endreaches a position below the pegwhereupon the arm 49 snaps back towardsits stop 53 and in so doing it momentarily knocks the arm 55 and itslimb 54 backwards thereby enabling the head 42, hitherto held away fromthe vertical plane of displacement of the pegs by the arm 55, to movetowards the conveyor to an extent suflicient to cause the vacuumappliance 46 carried by the head to engage with the peg 27 and apply therequired suction effort through the hole 14 of the package 10 carried bythe peg. By virtue of the considerable length of the arm 43, the arc ofdisplacement of the appliance 46 about the pivotal axis 44 of the arm,for all practical appliance 46 by virtue of the resiliency ofthe arm 43is maintained in contact with its co-operating peg 27 until the head 42moving behind the pivotal arm 58, i.e. between the latter and theconveyor 21, slides on to the ramp 62. It will be appreciated that theoperative zone of the ramp 62 at which separation of the appliance 46from its peg 27 takes place is such that by the time the head 42 reachessaid zone it will have lifted the arm 58 from engagement with the rampand passed between it and the ramp, thereby enabling the arm 58 toresume a position with its free end 61 engaging the ramp. Accordingly inreturning to its original position the arm 43, with its head 42 andvacuum appliance 46, is not only pulled by the spring 45 to the left infront of the arm 58 (Figures 8 and 10), but it is also displaced awayfrom the conveyor 21 and its pegs 27 to such an extent that, by the timeit reaches a position to the left of the arm 58 (Figure 8), it isautomatically reset in front of the arm 55 ready for the vacuumizingoperation on the package 10 carried by the next peg 27.

It will be appreciated that numerous modifications may be adoptedwithout departing from the scope of the invention as determined from theclaims. Thus for example if the insert 16 is not to be incorporated aspart of the final package for advertising or descriptive purposes, itmay take the form of a tongue of metal, cardboard or other rigid orstiff material which is mounted upon the vacuumizin-g and sealingmachine and is automatically inserted into a package before thetemporary sealing thereof, and is automatically withdrawn from thepackage after the final sealing has been performed. As in the insert ofFigures 3 and 4 this tongue is holed at 15 and slot-ted at '18 betweenthe hole and one edge 19 of the tongue.

Where a removable insert capable of repeated use is vacuum applicationand lower sealing along the band 33a of the same package, may beachieved with the aid of a composite head with the vacuum orificethereof located between upper and lower sealing jaws or rollers.

It will be appreciated that changes in the details, which have beenherein described and illustrated for the purpose of explaining thenature of the invention, may be made by those skilled in the art withoutdeparting from,

the principle and scope of the invention as determined by the appendedclaims.

I claim:

l. The herein described method of forming a vacuumized packagecomprising, forming a tubular sleeve of heat sealable film having closedsides and at least one open end, forming heat sealed spots in oppositesides cooperating to define a lower fill compartment and an upper wallspacing member receiving compartment, forming an aperture in at leastone wall of said last named compartment, placing fill in the fillreceiving compartment, and placing a thick wall spacing member having aslot formed therein in communication with one edge thereof in the memberreceiving compartment with said slot in registry with the wall apertureby orientation of said one edge of the member against the heat sealedspots with said slot opening from said one edge of the member toward thefill receiving compartment, sealing the ends of the sleeve, andevacuating the interior of the sealed sleeve through the member slot andsleeve aperture and providing a transverse seal isolating thecompartments.

2. The method defined in claim 1 modified by providing registeringapertures in both walls of the sleeve by simultaneously punching throughthe opposing walls of the sleeve with the wall spacing member thereinand with the apertures registering with the slot in the spacing member.

References Cited in thefile of this patent UNITED STATES PATENTS way;

